Any time you barter with someone, accepting property in exchange for goods or services, the value of the property is equal to the value of the item or service for which it is exchanged. If you accepted the house in exchange for a debt of $49,000, the basis of the house is $49,000. If the house was to pay a business debt, then it should have been reported on your 2015 income tax return. If it was to repay a loan, then the exchange was not reportable.
If you invested nothing in the house, and sold it for $46,500, then you would have a loss of $2500 increased by any expenses of sale.
Publication 525 explains more about IRS
rules regarding bartering.
